1. Field of the Invention
A putter head, more particularly a putter head having a cavity in the heel portion and a cavity in the toe portion, which cavities open to the face of the golf club.
2. Background Information
Golf is a game of precision--precision in the mechanics of the player attempting to properly swing the golf club, precision in addressing the ball, and also in the equipment he or she chooses. Precision plays an important part in the design of the golf club, where small changes in shape, technical specifications, weight distribution, or the like can result in large differences in the flight or path of the golf ball.
In the design of putters, balance, weight distribution and feel are very important. The intangible qualities of "feel" and "balance" vary from putter to putter, and each designer must rely on his own perception of what is desirable. With regard to weight distribution, however, putting design has evolved in an effort to provide the player with a putter head that will exhibit stability in the forward stroke, and impart as true a roll as possible to the golf ball, even in the incidence of off-center hits.
One feature commonly used in prior art to create stability is offsetting the centerline of the shaft so that it is forward of the face of the putter head. Whether this is achieved through the design of a connecting hosel or a bend in the shaft itself, this offset increases the linear distance between the center line of the shaft and the center of mass of the putter head, thereby increasing the moment of inertia of the putter head and helping the golfer produce a more stable forward stroke. Generally speaking, the greater this measurement, the more stable the putter head will be in the forward stroke, and the more resistant to twist at impact on off-center hits. However, there is a practical limit to which the hosel may be offset and still be visually acceptable to the majority of golfers.
Prior art typically managed the distribution of mass in the putter head solely by shaping the exterior surfaces, but some designs also rely on the use of additional weights, generally of lead or brass. Conventional design also has tended to utilize a hollow cavity to the rear of the putter head behind the central portion of the striking face, which cavity separates weight to the heel and toe areas. Such heel and toe weighting has become accepted and is commonly used as a method of increasing a putter head's pre-impact stability and its resistance to twist at impact on off-center hits. Conventional designs of this type have tended to shape the outside surfaces so that weight is concentrated low and forward of the geometric center of the putter head, thereby giving the putter head a low, forward center of gravity.
In the present invention, the applicant has designed a putter head with additional hollow cavities in the heel and toe areas of the putter head, open from the striking face, which may be left open, covered with a face plate, or filled with a low-density material. That is, applicant has further managed weight distribution in a putter head by creating voids open to the face, in addition to the specific shaping of the exterior surfaces. The resulting removal of mass low and forward in turn concentrates weight to the rear and upward in the putter head, thereby creating a higher and more rearward center of gravity than would be found in a conventional putter head of similar outside dimension and/or weight.
The present invention allows applicant to construct a putter head with an increased moment of inertia for a given set of exterior dimensions and a visually acceptable amount of offset than would be achievable with conventional design art. The result of utilizing applicant's invention is that the putter head thus constructed will exhibit improved stability in the forward stroke and will have greater resistance to twist on off-center impacts with the ball. In addition, applicant's method raises the center of gravity of the putter head to be more directly in line with the center of mass of the golf ball, resulting in a truer roll being implied to the ball at impact.
Applicant provides the novelty of using cavities open from the face of the club for the purpose of center-of-gravity management. The specific shaping of the cavities may be used to selectively distribute the weight, and thus manage the specific location of the center of gravity of the putter head. This allows significant improvement of the pre-impact stability of the club, as well as to improve the consistency of the path of the ball following impact, especially on off-center hits. Here, applicant uses the cavities to remove weight from the lower front portion of the putter head, at the extreme heel and toe areas, which resulting voids cause a shift of the center of gravity upward and to the rear of the putter head. When combined with a typical, hollow cavity to the rear of the central portion of the face of the club, a high moment of inertia is created.
Applicant's cavities may be left open, covered with a face plate or filled with epoxy resin or other low-density material. Given a typical putter head target weight of 300 to 350 grams, applicant can provide a putter head within a range such that a high moment of inertia is maintained for improved pre-impact stability and resistance to twist at impact (especially for off-center hits) while increasing the height of the center of gravity so that it is more in line with the center of mass of the golf ball.